Q.Answer the following question.
Which of the following redox couple is stronger reducing agent?
a. Li (E0 = -3.05 V) and Mg (E0 = -2.36 V)
b. Zn (E0 = -0.76 V) and Fe (E0 = -0.44 V)

A displacement reaction such as Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s) can be run either by simple direct contact (dipping zinc into copper sulfate solution) or by physically separating the oxidation and reduction into two containers -- zinc metal in zinc-salt solution, copper metal in copper-salt solution -- linked by an external wire (for electron flow) and a salt bridge (for ion flow to complete the circuit). This two-container arrangement is a Daniell cell, a simple electrochemical cell: zinc, where oxidation happens, is the anode (negative electrode); copper, where reduction happens, is the cathode (positive electrode); and the whole spontaneous redox reaction is converted directly into a measurable, usable flow of electric current. The electrical potential set up at each electrode is its electrode potential, and the two species linked by electron transfer at one electrode (e.g. Zn(s)/Zn²⁺(aq)) form a redox couple. The standard electrode potential ($E^0$) is this potential measured with every species at unit concentration and 298 K, referenced against the standard …